Method of firing steam generators



June 11, 1940. M. FmscH 2,204,351

11m-Hon oF FIRINGSTEAM GENERATORS I Filed Nov. 19,` 1936 3 Sheets-SheetA1 June 11, 1940.4 M, FR|$H 2,204,351

' uETHon oF FIRING s'rEAu GENERATORS Filed Nov. 19, 1936 3 .Sheets-Sheet3 psichica Jucc 11, 1940 'ME'rno-n oF-FIRING PATENT ,o1-FICE STEAMGENEnA'rons Martin Frisch, Cranford, N. J., signor Ato Footer Y WheelerCorporation, poration of New `York Application November 19, 1936, scric1New York, N. Y., a corv 9 claims. (o1. 12a-333)A AThis invention relatesto steam generators and more particularly pertains to methods of firingsteam generators and the'like. n

The invention providesa novel method of flring steam generators and thelike which results in complete utilization of the generator furnacevolumeirrespective lof the load on theigenerator;

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provides maximum ash deposition in the furnace or'furnaces, and attainsmore complete and more rapid combustion ofthe fuel employed than hasheretofore' been attained in the art.

The invention will be understood from the fol-V lowing description whenconsidered in connection with the accompanying drawings forming a partthereof in which:

Fig. l is a transverse vertical sectional view of steam generatingapparatus arranged for carrying out the method of the present invention;

Fig. 2 is a horizontal sectional view taken sub-k in the upper portionoffront wall I of each stantially on line 2-2 of Fig. l; and

Fig.- 3 .is a side elevationalview of the apparatus with certain partsinsection.

Like characters of reference designate the v same or similar parts inthe several views.

Although the invention is disclosed in connection with, or a's beingcarried out in, a vertical straight tube type of steamrgenerator havingtwo furnaces flanking the steam generating sectionv of the generator,-itwill be understood that the invention is capable of being carried out inother types of steam generators and in generators hav- Aing'only asingle furnace or having more than two furnaces.

Referring tothe drawings, the steam generator illustratedv is enclosedin a` casing having la front wall III, a rear wall II and sidewallsl|2and I3. 'I'he steam generating -section I l is disposed intermediate tworectangular furnaces I5 and I6.

' through a steam pipe 28 toa superheater. In'

through la.' plurality of steam risersv 26 withV a` steam drum 21, fromwhich steam is conducted addition to the relatively small tubes I1,` thesteam generating section includes a plurality of i rows of Vsomewhatlarger straight vertically` disposed tubes 29.l A superheater consistingof a plurality of small loop tubes 30 is disposed at the .inlet end of`the steam generating section Il. The steam generatingsection isseparated at its sides from the furnaces I5 and |6 by means ofthe walls3| and'32 which may be of any suitable form and if desired, may consistof a plurality. of armor blocks secured to water wall tubes. SlagAscreens 33 and 34 are lisposed between the forward ends of walls 3| and32 respectively and the front wall III of the-boiler casing. All of thewalls of the furnaces I5 and I 6 are water cooled by waterwall tubes 35and 38 respectively. If desired however, for low capacityinstallations,vthe firing Wall and the rear Wall of each of the furnacesmay be installed without Water cooling.

In the form of the invention illustrated, the furnaces are fired by afuel burner 31 disposed furnace and by a burner 38 disposed in the lowerportion of the front wall of each furnace. These burners are arranged todischarge jets of fuel and primary air through the spaces between thewater wall tubes 35 -and 36 and may be of the form disclosed andvclaimed in my copending application Serial No. 444,906, led April 17,1930. Seconda,-

ary air is supplied to the burners through air ducts 39 which deliver.the air to air casings 40 disposed at the outer side of 4the front wall4III of each of the furnaces. Secondary air from the casings lll flowsthrough a pluralityof air passages II disposed above each of the fueljets. of

the burners 31 and 38 and simultaneouslyv through a plurality of airpassages 42 disposed below each of the fuel jets of these burners. Thevolume and velocity ofthe secondary air discharged through these airpassages may be controlled by suitable means such as dampers or the likeso that the resulting streams of gases or products of combustion may bedirected horizontally,v

zontal path from the fr ont end of each furnace Kto the rearend thereofand the stream of products of combustion from the lower burner 38 ineach furnace simultaneously flows in a horizontal path from the frontend of the furnace through the lower portion thereof tothe rear end ofthe furnace. Adjacent the rear end of each furnace the upper streamturns downwardly and the lower stream turns upwardly and the two streamsimpinge upon and mix with each other as they turn through an angle ofapproximately 180. The resulting stream ows toward the front end of eachfurnace through the central portion of leach furnace intermediate theupper and lower streams. When these resulting streams rea-ch the frontend of each furnace, each turns through an angle of 90 in`a horizontalplane and passes over the slag screen disposed at the outlet of eachfurnace and enters the chamber 45 disposed at'the forward end of steamgenerating section I4 a-nd between the furnaces l5 and i6. In thischamber the two streams of products of combustion issuing from thefurnaces impinge upon and mix with each other and thereafter changetheir direction of ow through another angle of 90 in a horizontaldirection and ow over the superheater 3l] and pass in a single passthrough the steam generating section i4 over the tubes 29 and l1 andpass out through flue 46 at the front end of the steam generatingsection and flow downwardly therein through the return bend portion d1and upwardly through 'the vertically disposed portion 48 into an induceddra-ft fan 49 and thereafter into a stack 50. An economizer may beinstalled in the return bend section 41 of the ue and an air heater 5|may be employed in the section 48. Air is forced through the air heaterby a forced draft fan 52.

With this method of firing, it will be .perceived that all, orsubstantially all, of the furnace Volume of each furnace is fullyutilized by reason of the fact that streams of products of combustionare continuously owing through the upper and lower portions of eachfurnace in the same direction and through the central portion of eachfurnace in the opposite direction. "Additionally, at the point or zonein each furnace where the streams of 'products of combustion turn tobegin their return toward the front end thereof, intensive mixing occurswhich results in the speeding up of combustion to a maximum and thereduction of stratification' to a minimum. Moreover, it Will beperceived that each of the streams of products of combustion is forcedto abruptly change its direction of flow twice prior to entering thesteam generating section and each of these changes in ow direction isthrough an angle of approximately 180, the first turn being in avertical plane and the second turn in a horizontal plane. With theseabrupt changes in flow direction a larger proportion of suspended ash inthe streams will be precipitated within the furnace than has beenaccomplished in the art heretofore.

'I'he method of the present invention may be carried out in apparatusother than the specific form of the steam generator herein disclosed.

Additionally, it will be understood that variations may be made in themethod and in the several steps thereof without transcendirrg theprinciples of the invention. For example, a vsingle stream of productsof combustion may be produced in each furnace which will fiowpractically through, the entire furnace voliune prior to entering thesteam generating section, substantially in the manner in which one ofthe streams ows in lthe form of the invention disclosed. In` this event,there will be no mixing of separate streams in the furnaces, as in theform disclosed. 'I'he single stream of products of combustion will beproduced, preferably, by a burner, or tier of burners, so disposed inthe lower portion of each furnace that'the ame stream or the stream ofproducts of combustion will pass to the rear of the furnace in the lowerpart thereof, and after turning the stream returns through the centraland upper portions of each furnace. Other variations will occur tothoseskilled in the art. Accordingly, no intention is entertained to limitthe invention except by the scope of the appendedclaims.

What is claimed is:

1. The method of firing a steam generator which comprises producing aplurality-of separate, vertically disposed, substantially parallelstreams of products of combustion in a furnace, causing said streams toabruptly change their directions of fiow in a vertical plane andvtoimpinge upon and mix with each other and to flow through the furnace ina direction substantially parallel to the separate streams, and causingthe resulting stream to abruptly change its direction of ow prior toflowing in heat' exchange rela' parallel to the separate streams, andcausing the resulting stream to abruptly change its direction of ow in asubstantially horizontal plane prior to owing in heat exchangelrelationship with the steam generating surface of the generator.

3. 'I'he method of ring a steam generator which comprises producingseparate streams of products of combustion in the upper and lowerportions respectively of a furnace connected with the steam generatingsection of the generator, causing said streams to ow through thefurnacein substantially parallel relationship, causing said streams to abruptlychange their directions of ow toward each other and to impinge upon andmix with each other, causing the resulting stream to flow through thefurnace between said separate streams inra direction opposite theretoand causing the resulting stream to abruptly change its direction offlow prior to flowing into heat exchange relationship with the steamgenerating surface of the generator.

4. The method of flring a steam generator which comprises producingseparate streams of products of combustion in the upper and lowerportions respectively of an end portion of a furnace connected with thesteam generating section'of the generator, causing said streams to owthrough the furnace in substantially parallel relationship, causing saidstreams -to abruptly change their directions of ow toward each other andto impinge upon and mix with each other, causing the resulting stream toflow through the furnace between said separate streams in a directionopposite thereto and causing the resulting stream to abruptly change itsdirection of ow prior to owing into heat exchange relationship with thesteam generating surface of the generator.

5. The method of vfiring a steam generator which comprises producingseparate streams of products of combustion the upper and lower portionsrespectively of an end portion of a. fur- 4each furnace to flow naceconnected with the steam generating section of the generator, causingsaid streams to flow through the furnace in substantially parallelrelationship, ruptly change their directions of flow toward each otherand to impinge upon and mix with each other,v causing the resultingstream to iiow through the furnace between said separate streams in adirection opposite thereto and causing the resulting` stream to abruptlychange its 4direction of flow in a substantially horizontal plane priorto flowing into heat exchange relationship with the steam generatingsurface of the generator.

6. 'Ihe method of tiring a steam generator having a steam generatingsection connected toa plurality of laterally disposed furnaces whichcomprises producing a stream of products of combustion in each furnace,causing the stream in each furnace to flow successivelyin oppositedirections through different, vertically spaced portions thereof and toabruptly change its direction of flow in its passage therethrough, andcausing each stream to abruptly change its direction of flow prior topassing into heat exchange relationship with the steam generatingsection.

7. The method of firing a steamgenerator having a steam generatingsection connected to a plurality of laterally disposed furnaces whichcomprises producing a stream of products of combustion in eachsuccessively through different, vertically disposed portions thereof andto abruptly change its direction of flowxin its passage therethrough andcausing each stream to abruptly change its direction of flow and toimpinge upon and mix with the stream from ancausing said streams toabfurnace, causing the stream inv other furnace prior to passing intoheat exchange relationship' with the steam generating section.

8. The method of firing a steam generator having a steam generatingsection connected to a plurality of laterally disposed furnaces whichcomprisesv producing a stream of products of combustion in each furnace,causing the stream in each furnace to flow successively throughdifferent portions thereof and to abruptly change its direction 'of flowin its passage therethrough, and causing each stream to abruptly`changeits direction of flow and to impinge upon and mix with the stream fromanother furnace prior to passing' into heat exchange relationship withthe steam generating section.

9. The method of ring a steam generator having a steam generatingsection anda furnace disposed at each side thereof and connectedtherewith which comprises producing separate streams of products ofcombustion at one end of each furnace, one stream adjacent the upperportion of each furnace and another stream adjacent fthe I lowerportion, causing the streamslin each furnace to now therethroughinvsubstantiallyvparallel relationship, to abruptly change theirdirections of `flow toward each other and to impinge upon and mix witheach other, causing the resulting stream in each furnace to flowtherethrough between thel upper and lower streams and in the oppositedirection, causing the resulting stream in each furnace to abruptlychange its direction of flow and to impinge upon and mix with the streamfromlthe other furnace and causing said mixed streams to flow in onepass through the steam generating section..

' FRISCH.

